1.264 Lecture 14. SOAP, WSDL, UDDI Web services

Transcription

1 1.264 Lecture 14 SOAP, WSDL, UDDI Web services

2 Front Page Demo File->New Web (must create on CEE server) Choose Web type Add navigation using Format->Shared Borders (frames) Use top and left, include navigation buttons Go to Navigation view, drag pages into workspace Save each page before viewing in browser Create structure, layout of Web site Navigation window Organize files and folders Folders window Import and export files File->Import, don t copy Tests and repairs hyperlinks Hyperlinks view, Tools->Recalculate Hyperlinks

3 Simple Object Access Protocol: SOAP Microsoft proposed the SOAP standard, having given up on ActiveX/COM for Internet applications SOAP is essentially XML and HTTP Intent is to introduce no new technology for distributed computing beyond what is being used SOAP adds some headers to HTTP; no other changes Other middleware solutions are incorporating SOAP (CORBA mostly; COM (MS) moving to SOAP directly) Key element of SOAP: New MIME type: text/xml Agreed definitions of data types, mandatory values, etc. SOAP implements all the key features of legacy middleware (COM and CORBA) at a fraction of the complexity

4 SOAP URLs replace the repositories and registries of COM and CORBA A search engine can be used to dynamically locate remote objects unknown to the client application when designed HTTP POST and response replace application programming (in legacy CORBA and COM IDLs) SOAP (HTTP and XML) is all in text rather than binary, so it s much easier to interoperate across machines and debug it SOAP is sufficiently efficient for most machine-machine communication Don t use it on a single machine: use native COM or Java mechanisms

5 UDDI Universal Description, Discovery and Integration UDDI Business Registry (UBR) is global public directory of businesses and services Users query UBR to discover Web services and get info to use them White pages, yellow pages, green pages (services) Uses SOAP to publish, edit, browse the UBR WSDL (Web Services Description Language) is used to describe the services Information at Microsoft and IBM (see homework 5) Brief demo

6 WSDL Contains: Description and format of messages that can be passed in <types> and <message> tags Direction of message passingin <porttype>: Request-only, request-response, response-only Message encoding in <binding> element (literal, etc.) Location where service is offered in <service> element

7 WSDL Example <definitions name="stockquote" targetnamespace=" xmlns:tns=" xmlns:xsd1=" xmlns:soap=" xmlns=" <types> <schema targetnamespace= xmlns=" <element name="tradepricerequest"> <complextype> <all> <element name="tickersymbol" type="string"/> </all> </complextype> </element> <element name="tradeprice"> <complextype> <all> <element name="price" type="float"/> </all> </complextype> </element> </schema>

8 WSDL, p.2 <message name="getlasttradepriceinput"> <part name="body" element="xsd1:tradepricerequest"/> </message> <message name="getlasttradepriceoutput"> <part name="body" element="xsd1:tradeprice"/> </message> <porttype name="stockquoteporttype"> <operation name="getlasttradeprice"> <input message="tns:getlasttradepriceinput"/> <output message="tns:getlasttradepriceoutput"/> </operation> </porttype> <binding name="stockquotesoapbinding type="tns:stockquoteporttype"> <soap:binding style="document transport=" <operation name="getlasttradeprice"> <soap:operation soapaction=" <input> <soap:body use="literal"/> </input> <output> <soap:body use="literal"/> </output> </operation> </binding> <service name="stockquoteservice"> (etc. defines URL for service)

9 SOAP, UDDI and WSDL POST /StockQuote HTTP/1.1 Host: Content-Type: text/xml; charset="utf-8" Content-Length: nnnn SOAPAction: "Some-URI" From UDDI <SOAP-ENV:Envelope xmlns:soap-env=" SOAP-ENV:encodingStyle=" <SOAP-ENV:Header> <t:transaction xmlns:t="some-uri" SOAP-ENV:mustUnderstand="1"> 5 </t:transaction> </SOAP-ENV:Header> <SOAP-ENV:Body> <m:getlasttradeprice xmlns:m="some-uri"> <symbol>sunw</symbol> </m:getlasttradeprice> </SOAP-ENV:Body> </SOAP-ENV:Envelope> WSDL

10 XML, SOAP, UDDI, WSDL Summary XML is built into major Internet applications developed in the last months XML is expected to be the dominant protocol for Internet commerce, supply chain, engineering collaboration and other cross-organization activities XML document type definitions (DTD, XSchema) are difficult to standardize but there are many efforts underway RosettaNet, other exchanges SOAP for the most general interoperability XML will replace legacy middleware (COM and CORBA) over time, and will probably be the dominant payload on the Net See article.jsp?l=webservices-dev-guide SOAP in wide use now; WSDL coming into use UDDI in early stages

11 Web services XML allows heterogeneous environments to share information over the Web It now allows means to share process also. Keys are XML and HTTP/SOAP, each with wide acceptance. One way of building Web services: Create and deploy Web service using programming language and Web server of your choice Define Web service in WSDL Register Web service in UDDI User searches UDDI to find service and its parameters User invokes service using SOAP, which has format for representing parameters and return values over HTTP

12 Web services, cont. This is ok for simple services Extended services need standards for common transactions (orders, catalogs, engineering design documents, etc.) ebxml (ebusiness XML) is set of XML specifications Java and.net both support SOAP, WDSL and UDDI ebxml is evolving and will likely be supported by Java and.net Java (J2EE) and.net support Web services with tools for reliable, scalable, high-performance implementations Implementation details vary; standards are the same J2EE is a standard; many vendors build products.net is a product, built by Microsoft

13 J2EE Web Services Web browser Business partner or other system Applications(Java) W SOAP,UDDI,WSDL,ebXML CORBA IIOP HTTP Firewall Web svr Servlets Java Server Pages Enterprise Java Beans SQL Proprietary SOAP,UDDI,WSDL,ebXML Back end Database Legacy Applications Business partner or other system

14 .NET Web Services Web browser Business partner or other system Applications (VB) W SOAP,UDDI,WSDL,BizTalk ActiveX/COM HTTP Firewall Web svr ASP.NET (Active Server Pages).NET Managed Components (ADO.NET-ActiveX Data Objects, COM+) SQL Proprietary SOAP,UDDI,WSDL,BizTalk Back end Database Legacy Applications Business partner or other system

15 .NET and J2EE Property Implementation Product vendor Web pages Server components Database access Middleware Primary language Portability J2EE Standard Many (Sun, IBM, etc) Java Server Pages Enterprise JavaBeans JDBC and SQL/J SOAP, UDDI, WSDL Java Across many vendors.net Product Microsoft Active Server Pages.NET Components ADO.NET (on ODBC) SOAP, UDDI, WSDL C++, C#, VB Microsoft only

16 .NET and J2EE Differences between them are fairly small Some secondary differences: ASP.NET is independent of client device, and user interfaces can work on PCs, handheld devices, etc. without change. JSP requires changes..net Components are simpler than EJBs. If you don t need additional features,.net is simpler. Otherwise you have to build the extra features yourself, which is more complex (such as nested transactions, state machines) J2EE tools come from many vendors and don t interoperate as smoothly as.net, which is all Microsoft J2EE is more mature;.net is new and a major change

17 J2EE Support for XML, UDDI, SOAP, WSDL JAXP: Java API for XML Parsing Supports SOAP, UDDI, WSDL and ebxml JAX/RPC: Java API for XML Remote Procedure Calls Supports program-to-program communication via SOAP JAXM: Java API for XML Messaging Supports automated handling of XML messages using ebxml rules. Handles headers, errors, etc. ebxml: XML specifications, core components E.g., dates, taxation, account, contract See ebxml.org for more info JAXB: Java API for XML Binding Converts XML to/from Java objects XSLT: XML Stylesheet Language Transformations Converts from one XML document to another JCA: Java Connector Architecture Includes adapters for legacy systems to/from Java, XML

18 .NET Support for XML, UDDI, SOAP, WSDL ASP.NET and ADO.NET offer roughly the same features for XML documents as J2EE BizTalk rather than ebxml is the standard supported BizTalk is Microsoft proprietary and appears to be losing the war MS does not support ebxml XSLT is supported UDDI, WSDL, SOAP are supported directly SOAP was proposed by Microsoft

19 Business partner or other system Web Services Applications Web browser W SOAP,UDDI,WSDL,ebXML CORBA IIOP HTTP Firewall Web svr Servlets or Server-side scripts Enterprise Java Beans or COM+/MTS Java Server Pages or Active Server Pages SQL Proprietary SOAP,UDDI,WSDL,ebXML Back end Database Legacy Applications Business partner or other system